The Jackson Laboratory (TJL) was founded in 1929 by Dr. Clarence Cook Little as a mammalian genetics research center focusing on the problem of cancer. The long term goal of TJL Cancer Center program is to contribute to basic understanding of the genetic determinants of cancer. Expertise in the genetics and biology of the laboratory mouse is the predominant strength of TJL Cancer Center and is the centerpiece of the cancer research conducted here. The mouse represents a powerful mammalian model for human genetic organization and regulation, modes of inheritance, and disease. Researchers are identifying sets of associated genes participating in complex diseases and beginning to elucidate their modes of interaction. Epigenetic factors influencing gene action, mutagenesis, and cancer risk are being isolated and identified. Other investigators are discovering the molecular regulation of developmental processes, the dysregulation of which can lead to cellular transformation. A wide array of inbred, congenic, and mutant strains of mice are available for investigations into the control of immune functions and development of immunotherapies for cancer.